Device for withdrawing filling material from bags

ABSTRACT

A sealing member inside the bag and a withdrawing member outside the bag can be interplugged and cooperate by complimentary conical sealing surfaces to dispense flowable material from the bag. A retaining member is attached to the outer side of the bag wall and clamps a portion of the bag wall between the retaining member and the sealing member to allow a plastic deformation of that portion by the withdrawing member until it ruptures.

The invention relates to a device for withdrawing flowable fillingmaterial through a wall of a bag having flexible walls.

PRIOR ART

Frequently, a flowable filling material, particularly resin-likeplastic, shall be withdrawn from a bag without coming into contact withthe atmosphere or with the human skin. Also, only a partial amount shalloften be withdrawn, and it is then desirable that a detachable closurecan be conveniently provided at the bag. For this and other purposes,devices of the kind initially described have been developed.

From the German patent specification 25 25 000, a device for withdrawingflowable filling material has become known wherein separating meansprovided at the withdrawing part consist of a central conical tip whichcomprises a through-going opening in its sidewall. A flat conicalsurface is connected to its base which forms a sealing surface andco-operates with a matching sealing surface of a sealing part inside thebag. Upon the plugging-together, the bag wall must be severed before thesealing surfaces meet and a further relative movement in the pluggingdirection is no longer possible. In this reference, nothing is saidabout how the interplugged parts are held together.

From the German patent specification 31 29 777, a device for withdrawingflowable filling material through a flexible wall of a bag has becomeknown wherein an annular coupling portion is adhered to the inner wall othe bag. A further coupling portion serving as the withdrawing part istubular and includes annular ridges saw-teeth-like in cross section atthe outer side thereof. The withdrawing part is adapted to penetrate thebag wall in the area of the opening of the annular inner couplingportion with the annular ridges snappingly engaging the edge of theopening of the annular coupling surface of an annular ridge facingoppositely to the plugging direction engages the associated surface ofthe annular coupling portion under pretension which is generated by thepierced bag wall. The known withdrawing device requires a fixation ofthe annular coupling portion in the interior of the bag which isrelatively expensive in production.

The British patent specification 1 104 359 discloses a withdrawingdevice wherein an annular withdrawing part is sealingly attached to theinner wall of the bag, e.g. by welding. The sleeve-like withdrawing partincludes an annular groove which is engaged by the edge of an opening ofan annular sealing portion by a snapping operation when the withdrawingpart pierces the bag wall and is plugged into the sealing portion. Thewithdrawing part and sealing part have annular cylindrical sealingsurfaces which serve to restrict a leakage of the flowable mediumbetween the withdrawing and sealing parts.

With the known devices, the bag wall first is fixed before it is piercedby suitable separating means. Such devices may work satisfactory if thepressure during the dispensing process is not too large. In case thepressure exceeds predetermined values, it may occur that the sealingcannot be maintained sufficiently or the filling material leaks out dueto failures in the sealing and/or a rupture of the bag wall. This has tobe absolutely avoided for obvious reasons.

SUMMARY OF THE INVENTION

The invention provides a device for withdrawing flowable fillingmaterial through the flexible wall of a bag which effectively restrictsan insufficient sealing or a rupture of the bag wall in the area of thewithdrawing device and thus an undesired leakage of the material.

The device of the present invention for withdrawing flowable fillingmaterial through a wall of a bag having flexible walls comprises asealing member arranged inside said bag, which has an annular sealingsurface and an axial through-going passage approximately circular incross section and extending substantially perpendicular to said annularsealing surface, which passage defines an axial sealing surface, and awithdrawing member arranged outside the bag. The withdrawing member hasa tubular portion provided with an outer annular axially extendingsealing surface and the tubular portion is adapted to be plugged intothe passage of the sealing member after the flexible bag wall has beenpierced by the free end of the tubular portion. After the axial sealingsurfaces of the tubular portion of the withdrawing member and thepassage in the sealing member are brought into mutual engagement, aconical end portion on the tubular portion, having the outer sidethereof tapering towards the free end, makes complimentary engagementwith a conical portion of the sealing member. Further, a retainingmember, adapted to be sealingly attached to the outer side of saidflexible bag wall preferably by an adhesive, and having a throughbore,the diameter thereof being equal to or slightly larger than the outerdiameter of said tubular portion, is adapted to be oriented on theoutside of the bag such that the passage of the sealing member and saidthroughbore of the retaining member are approximately coaxial.

DESCRIPTION OF THE ACCOMPANYING DRAWING

Several presently preferred embodiments of the invention will bedescribed subsequently in more detail in connection with drawing,wherein:

FIG. 1 is a cross-sectional sideview of parts of a device according tothe invention;

FIG. 2 is a cross-sectional view of the sealing member of the device ofFIG. 1 inside a bag filled with filling material;

FIG. 3 is a fragmentary cross-sectional view similar to FIG. 2additionally including the annular retaining member of FIG. 1 attachedto the outer side of the bag wall;

FIG. 4 is a cross-sectional view similar to FIG. 3 additionallyincluding the withdrawing member of FIG. 1 shortly prior to itsplugging-in into the sealing member;

FIG. 5 is a view of the device according to the invention showing a modewherein the withdrawing member is completely plugged into the sealingmember; and

FIG. 6 is a view of the bag shown in FIGS. 2 to 5 without a withdrawingdevice after being deformed by the withdrawing device in the mode shownin FIG. 5.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The device according to the invention includes a tubular withdrawingportion with a conical end portion, the outer surface thereof taperingconically towards the free end. A sealing member having a passage with aconical portion formed complimentarily to the end portion. A furtherfeature of the invention is represented by a retaining member sealinglyattachable to the outer side of a flexible bag wall, preferably by anadhesive. It includes a throughbore, the diameter thereof being equal toor slightly larger than the outer diameter of the tubular portion.

The sealing member is loosely placed inside the bag when it is filledwith the flowable material. If the contents of the bag is to bewithdrawn, first the annular retaining member is sealingly attached to adesired location on the outer side of the bag, preferably by means of anadhesive. According to an embodiment of the invention, an adhesive layercan be provided on the annular retaining member, preferably apressure-sensitive adhesive in order to achieve a simple attachment tothe bag wall. Thereafter, the sealing member inside the bag is alignedwith the retaining member until the bore of the retaining member and thepassage of the sealing member are approximately coaxial. The orientationof the sealing member is such that the conical portion of the passageenlarges towards the retaining member. For this purpose, it isappropriate to provide the sealing member with respective colored orother marks to allow the operator to determine the accurate placement ofthe sealing member. Thereafter, the tubular portion of the withdrawingmember is placed within the bore of the retaining member against theportion of the bag wall clamped between the retaining and sealingmember. Upon progressive axial pressure on the tubular portion, firstthe clamped portion of the bag wall is resiliently and finallyplastically deformed so that it is placed between the conical portionsof the tubular portion and the sealing member with a reduced thickness.Finally, the deformation and the stretching of the portion reaches anextent that it ruptures. By this, a passage is formed between theinterior of the bag and the tubular portion through which the contentsof the bag can be dispensed via the tubular portion or the withdrawingmember, respectively, in the known manner.

With the device according to the invention, thus, the wall of the bag isnot pierced or cut, rather, similar to a deepdrawing process is firstresiliently and thereafter plastically deformed to an extent that itruptures. By this, a portion of the deformed wall having a smallerthickness is pressed between the cones of the tubular portion and thesealing member. The described structure of the device according to theinvention and the sealing achieved thereby enables a dispensing of thecontents of the bag also under high pressure without running the riskthat the flowable material exits in an undesired manner. The maximumpressure which can be applied upon a dispensing operation is solelydependant on the burst strength of the bag.

According to an embodiment of the invention, the cone angle of the endportion and the passage is dimensioned such that a self-locking iseffected. Preferably, the cone angle is smaller than 5°. Theself-locking has the result that additional locking means to retain thetubular portion of the withdrawing member within the sealing member arenot necessary. However, in some cases, the contents of the bag mayprovide lubricating properties. Small amounts of the material may enterthe space between the stretched bag wall and the cone of the sealingmember and prevent an effective friction. For this case, an embodimentof the invention provides that the passage of the sealing memberincludes a locking portion or recess of larger diameter at the endopposite to the retaining member, and the end portion of the withdrawingmember has a radial annularly extending enlargement which snaps into thelocking recess when the tubular portion is plugged into the passage. Thetubular portion is of relatively hard plastic material while the sealingmember is of softer plastic material which preferably has resilientproperties. The outer diameter of the radial enlargement is slightlylarger than the smallest diameter of the conical portion of the passageso that a small deformation of the sealing member occurs temporarilyuntil the radial enlargement engages the locking recess. By this, afurther effect is achieved to effectively separate the stretched bagwall. The annular edge between the conical portion of the passage andthe locking recess can be shaped relatively sharp. Upon forcing theradial enlargement into the recess, the bag wall is bent at therelatively sharp edge and is sheared off.

The sealing member has to have a relatively large thickness to guaranteethat the clamped bag wall ruptures before the cones of the tubularportion and the sealing member interengage. It is understood that thethickness depends upon the material of the bag and the thickness of itswall.

In order to achieve the described coaxial alignment of the retaining andsealing member, these parts may have cooperating guiding means throughwhich the coaxial position of the parts is accomplished. In anembodiment of the invention, a recess is formed in the surface of thesealing member facing the retaining member, the recess accommodating aguiding portion of the retaining member and securing the sealing memberagainst lateral displacement. The plugging-in of the withdrawing memberinto the sealing member is facilitated if the bag is placed on a firmbase so that also the opposite side of the sealing member engages thebag wall. In order to allow a partial escape of the flowable materialout of the passage of the sealing member during the plugging-in of thewithdrawing member, the other end of the sealing member oppositelylocated to the retaining member may be provided with at least one radialgroove or a radial passage to establish a connection of the passage withthe interior of the bag.

Referring now to the drawing in FIG. 1, the sleeve-like or tubularwithdrawing member 10 is shown partially in cross section. The lowerportion 12 thereof has an outer cone 14 which tapers towards the freeend. An annular radial enlargement 16 is formed at the free end. Theother end of the withdrawing member 10 can be arbitrarily shaped toadapt it to a desired use. For example, it may be provided with a threador with another configuration in order to be connected with a containerto be filled.

The cone angle of the end portion 12 is less than 5°.

In FIG. 1, also the annular retaining member 18 is shown in crosssection consisting of plastic material and having a relatively smallthickness. The lower side thereof is provided with a layer 20 ofpressure-sensitive adhesive which is covered by a removable protectionlayer. The inner diameter of the annular member 18 is equal to orslightly larger than the outer diameter of the tubular withdrawingmember 10.

Finally, in FIG. 1 the annular sealing member is shown in cross sectionwhich has a thickness much larger than that of the retaining member 18.The outer configuration of the sealing member 22 is cylindrical. Thesealing member 22 includes an annular sealing surface including a recess24 at the front end facing the retaining member 18, with the diameter ofthe recess being slightly larger than the outer diameter of theretaining member 18. The annular sealing member 22 includes a passagetherethrough, defining an axial sealing surface, having a conicalportion 26 formed complementary to the conical portion 14 of withdrawingmember 10. An annular recess 30 joins to the conical portion 26 and hasa larger diameter. The smallest diameter of the conical portion 26 atthe edge 32 is slightly smaller than the outer diameter of the radialenlargement 16. The edge 32 joining the conical portion 26 of thepassage and recess 30 is shaped relatively sharp. The sealing member 22includes a plurality of radial passages 34 at the front end opposite torecess 24 which interconnect the passage and the interior of a bag.

In FIGS. 2 to 6, a bag 40 is shown filled with a flowable fillingmaterial 42, e.g. resin-like plastic material. The bag 40 is made of twosheets 44, 46 of plastic material forming the flexible walls of the bag40 and being welded at margin 48. Inside the bag, the annular sealingmember is loosely inserted. Selectively, the sealing member 22 may beattached to the inner side of the bag wall, e.g. by an adhesive orwelding.

In order to obtain access to bag 40 and to withdraw the filling material42, the annular sealing member 22 is placed at a desired location. Theoperator may simply determine the orientation of sealing member 22through a corresponding configuration thereof. The retaining member 18is adhered to the outer side of bag wall 44 as shown in FIG. 3. It isunderstood that annular member 18 may be continuously attached to bag 40prior to or shortly after the filling of bag 14, e.g. through anadhesive, ultrasonic welding or the like. If the retaining member 18 isnot permanently attached to bag 40, it forms a kit with the withdrawingmember 10 and can be delivered with bag 40.

The alignment of retaining member 18 and sealing member 22 isfacilitated by recess 24 which partially accommodates retaining member18 and secures sealing member 22 against lateral displacement. It isemphasized that a sufficient sealing has to take place between retainingmember 18 and bag wall 44.

As shown in FIGS. 4 and 5, withdrawing member 10 has to be positionedrelative to retaining member 18 for the withdrawing operation.Thereafter, withdrawing member 10 is placed into the bore of retainingmember 18 against portion 50 of bag wall 44 clamped between retainingmember 18 and sealing member 22. In the embodiment of FIG. 4, bag 40 isplaced on a base, not shown, so that the bag wall 46 engages the lowerside of sealing member 22. If the conical end portion 22 of withdrawingmember 10 is urged against portion 50, this first is resilientlydeformed and thereafter, stretched and finally plastically deformed sothat it results in a conically deformed portion 52 as shown in FIG. 6.The deformation is such that finally, the lower part of portion 52ruptures as shown at 54 before the conical portions 12, 14 and 26interengage. The radial annular enlargement 16 having a slightly smallerdiameter than the diameter of the relatively sharp edge 32 forces thestretched bag wall against the sharp edge 32 and effects a rupture ofthe bag wall at the latest when the enlargement 16 engages the annularrecess 30. This results in a locking operation effecting the withdrawingmember 10 to stay in the position shown even though a small friction mayoccur between the conical portions 12, 14 and 26, respectively, and ofthe filling material 42 being dispensed under high pressure.

A series of radial passages 34 enable an escape of a portion of thefilling material out of the passage of the sealing member upon thewithdrawing member 10 being plugged into sealing member 22 when the bagis placed on a base as shown in FIG. 4 and the bag wall 46 causes asealing of the lower end surface of sealing member 22.

We claim:
 1. A device for withdrawing flowable filling material througha wall of a bag having flexible walls, comprising a sealing memberarranged inside said bag and having an annular sealing surface and anaxial throughgoing passage approximately circular in cross section andextending substantially perpendicular to said annular sealing surface,said passage defining an axial sealing surface, and a withdrawing memberarranged outside said bag and having a tubular portion provided with anouter annular axially extending sealing surface, said tubular portionincluding a conical end portion and provided with an outer annularaxially extending sealing surface, said tubular portion being adapted tobe plugged into said passage of said sealing member after said flexiblewall has been pierced by a free end of said tubular portion, with saidaxial sealing surfaces of said tubular portion of said withdrawingmember and said passage being brought into mutual engagement,characterized in that said passage of said sealing member has a conicalportion substantially complementary to said conical end portion, withthe length of said conical portion of said withdrawing member and saidconical portion of said sealing member selected such that the materialof the bag wall rupture when said concial portions interengage, and thata retaining member is adapted to be sealingly attached to the outer sideof said flexible bag wall, said retaining member having a throughbore,the diameter thereof being equal to or slightly larger than the outerdiameter of said tubular portion, of said withdrawing member, with saidsealing member being adapted to be oriented such that said passage ofsaid sealing member and said throughbore of said retaining member areapproximately coaxial.
 2. The device of claim 1, wherein the cone angleof said end portion and of said conical portion of said passage isdimensioned such that a self-locking is achieved.
 3. The device is claim1 or 2, wherein said retaining member is defined by a ring of relativelysmall thickness.
 4. The device of claim 1, wherein said sealing memberis defined by a ring of relatively large thickness.
 5. The device ofclaim 1, wherein said retaining member and said sealing member haveco-operating guiding means for fixing the coaxial position of saidmembers.
 6. The device of claim 5, wherein said guiding means comprisesan end surface of said sealing member facing said retaining member,which end surface has a recess and a guiding portion of said retainingmember, wherein said recess is adapted to accommodate said guidingportion to prevent a lateral displacement of said sealing member.
 7. Thedevice of claim 1, wherein said passage of said sealing member on theend opposite to said retaining member has a locking recess of largerdiameter than said passage and said end portion of said withdrawingmember has a radial, annularly extending enlargement which engages saidlocking recess when said tubular portion is plugged into said passage.8. The device of claim 7, wherein an annular edge between said conicalportion of said passage and of said locking recess is formed relativelysharp.
 9. The device of claim 1, wherein said sealing member has atleast one radial groove or passage at the end surface opposite to saidretaining member to establish a connection of said passage of sealingmember with the outer periphery of said sealing member.
 10. The deviceof claim 1, wherein said tubular portion is made of relatively hardplastic material and said sealing member is formed of softer resilientplastic material.
 11. The device of claim 1, wherein one side of saidretaining member is provided with a layer of an adhesive, whichcomprises a pressure-sensitive adhesive which is covered by a removableprotection layer.